COMPAT: 32-bit indexing compat

xref pandas-dev#20939

Author: jreback

pandas/core/indexing.py

@@ -1318,7 +1318,7 @@ def _convert_to_indexer(self, obj, axis=None, is_setter=False):
                     (indexer,
                      missing) = labels.get_indexer_non_unique(objarr)
                     # 'indexer' has dupes, create 'check' using 'missing'
-                    check = np.zeros(len(objarr))
+                    check = np.zeros(len(objarr), dtype=np.int_)
                     check[missing] = -1
 
                 mask = check == -1